Thousands of Hollister residents can look forward to receiving better quality drinking water when the West Hills Water Treatment Plant goes into operation at the end of the month.

Located off Union Road by the San Justo Reservoir, the plant will treat surface water from the reservoir before it is mixed with local groundwater and distributed to approximately 4,000 households in the west and central regions of the city.

Water to other parts of Hollister is treated by the Lessalt Water Treatment Plant.

The new blend of drinking water will contain less groundwater, which is more salty than surface water.

“The local groundwater is salty because of marine sediment in the region,” said Jeff Cattaneo, district manager for the San Benito County Water District, during a recent tour of the new $30 million plant.

“If you go all the way back to [Hernandez Reservoir] you can find marine fossils up in the rocks there,” Cattaneo said. “It just naturally picks up the calcium and magnesium as it moves through that system.”

The West Hills Water Treatment Plant features innovative technology that utilizes power activated carbon and sand to quickly remove particles from water.

“There’s a recycle process so you’re reusing the sand and the carbon,” said Don Ridenhour, general manager for the Sunnyslope County Water District. “It’s supposed to be a really effective way to remove impurities.”

While the local water districts aren’t the first to use this method, Ridenhour said it’s not the norm.

“We went and toured another plant and I know of a few other plants that use this similar process, but it’s not the normal process used by every agency,” he said.

Bringing in high quality water will allow residents to get rid of their water softeners.

“Residents won’t need to use water softeners if they have higher quality water coming into the front end of their home,” Cattaneo said.

Because higher quality water is going into homes, higher quality wastewater is also coming out of homes. This water can then be treated and used as recycled water for agricultural uses.

“What this does is for every acre-foot of water we bring in from San Luis Reservoir that we deliver to Hollister residents and Sunnyslope customers, we get to use it twice,” Cattaneo said.

“We use it once for the residents and then it goes out and gets reused again by agriculture,” said Shawn Novack, water conservation manager for the Water Resources Association of San Benito County, which operates all water conservation and resource protection programs for Hollister, San Juan Bautista, the county water district and Sunnyslope.

The treated water will also help recharge and preserve the groundwater basin.

“We’re replacing the groundwater we’ve all been using with more surface water that’s imported from down south,” said Ridenhour.

The new water treatment plant is expected to treat 4.5 million gallons of water per day, compared to the Lessalt Treatment Plant, which treats 2.5 million gallons of water per day.

That’s a total peak capacity of 7 million gallons of water per day between the two plants, but officials said average production for an entire year is around 4.5 million gallons per day.

Depending on future demands, however, the West Hills plant can expand to treat up to 9 million gallons of water per day.

“Right now it’s looking like somewhere around 2025, but that could be accelerated or delayed depending on demand,” said Ridenhour.